Hunter0x7c7
2022-08-11 a82f9cb69f63aaeba40c024960deda7d75b9fece
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package trojan
 
import (
    "context"
 
    core "github.com/v2fly/v2ray-core/v5"
    "github.com/v2fly/v2ray-core/v5/common"
    "github.com/v2fly/v2ray-core/v5/common/buf"
    "github.com/v2fly/v2ray-core/v5/common/net"
    "github.com/v2fly/v2ray-core/v5/common/protocol"
    "github.com/v2fly/v2ray-core/v5/common/retry"
    "github.com/v2fly/v2ray-core/v5/common/session"
    "github.com/v2fly/v2ray-core/v5/common/signal"
    "github.com/v2fly/v2ray-core/v5/common/task"
    "github.com/v2fly/v2ray-core/v5/features/policy"
    "github.com/v2fly/v2ray-core/v5/proxy"
    "github.com/v2fly/v2ray-core/v5/transport"
    "github.com/v2fly/v2ray-core/v5/transport/internet"
)
 
// Client is an inbound handler for trojan protocol
type Client struct {
    serverPicker  protocol.ServerPicker
    policyManager policy.Manager
}
 
// NewClient create a new trojan client.
func NewClient(ctx context.Context, config *ClientConfig) (*Client, error) {
    serverList := protocol.NewServerList()
    for _, rec := range config.Server {
        s, err := protocol.NewServerSpecFromPB(rec)
        if err != nil {
            return nil, newError("failed to parse server spec").Base(err)
        }
        serverList.AddServer(s)
    }
    if serverList.Size() == 0 {
        return nil, newError("0 server")
    }
 
    v := core.MustFromContext(ctx)
    client := &Client{
        serverPicker:  protocol.NewRoundRobinServerPicker(serverList),
        policyManager: v.GetFeature(policy.ManagerType()).(policy.Manager),
    }
    return client, nil
}
 
// Process implements OutboundHandler.Process().
func (c *Client) Process(ctx context.Context, link *transport.Link, dialer internet.Dialer) error {
    outbound := session.OutboundFromContext(ctx)
    if outbound == nil || !outbound.Target.IsValid() {
        return newError("target not specified")
    }
    destination := outbound.Target
    network := destination.Network
 
    var server *protocol.ServerSpec
    var conn internet.Connection
 
    err := retry.ExponentialBackoff(5, 100).On(func() error {
        server = c.serverPicker.PickServer()
        rawConn, err := dialer.Dial(ctx, server.Destination())
        if err != nil {
            return err
        }
 
        conn = rawConn
        return nil
    })
    if err != nil {
        return newError("failed to find an available destination").AtWarning().Base(err)
    }
    newError("tunneling request to ", destination, " via ", server.Destination().NetAddr()).WriteToLog(session.ExportIDToError(ctx))
 
    defer conn.Close()
 
    user := server.PickUser()
    account, ok := user.Account.(*MemoryAccount)
    if !ok {
        return newError("user account is not valid")
    }
 
    sessionPolicy := c.policyManager.ForLevel(user.Level)
    ctx, cancel := context.WithCancel(ctx)
    timer := signal.CancelAfterInactivity(ctx, cancel, sessionPolicy.Timeouts.ConnectionIdle)
 
    postRequest := func() error {
        defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)
 
        var bodyWriter buf.Writer
        bufferWriter := buf.NewBufferedWriter(buf.NewWriter(conn))
        connWriter := &ConnWriter{Writer: bufferWriter, Target: destination, Account: account}
 
        if destination.Network == net.Network_UDP {
            bodyWriter = &PacketWriter{Writer: connWriter, Target: destination}
        } else {
            bodyWriter = connWriter
        }
 
        // write some request payload to buffer
        if err = buf.CopyOnceTimeout(link.Reader, bodyWriter, proxy.FirstPayloadTimeout); err != nil && err != buf.ErrNotTimeoutReader && err != buf.ErrReadTimeout {
            return newError("failed to write A request payload").Base(err).AtWarning()
        }
 
        // Flush; bufferWriter.WriteMultiBuffer now is bufferWriter.writer.WriteMultiBuffer
        if err = bufferWriter.SetBuffered(false); err != nil {
            return newError("failed to flush payload").Base(err).AtWarning()
        }
 
        if err = buf.Copy(link.Reader, bodyWriter, buf.UpdateActivity(timer)); err != nil {
            return newError("failed to transfer request payload").Base(err).AtInfo()
        }
 
        return nil
    }
 
    getResponse := func() error {
        defer timer.SetTimeout(sessionPolicy.Timeouts.UplinkOnly)
 
        var reader buf.Reader
        if network == net.Network_UDP {
            reader = &PacketReader{
                Reader: conn,
            }
        } else {
            reader = buf.NewReader(conn)
        }
        return buf.Copy(reader, link.Writer, buf.UpdateActivity(timer))
    }
 
    responseDoneAndCloseWriter := task.OnSuccess(getResponse, task.Close(link.Writer))
    if err := task.Run(ctx, postRequest, responseDoneAndCloseWriter); err != nil {
        return newError("connection ends").Base(err)
    }
 
    return nil
}
 
func init() {
    common.Must(common.RegisterConfig((*ClientConfig)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
        return NewClient(ctx, config.(*ClientConfig))
    }))
}